This study is designed to investigate several factors of the immune response to cervical chlamydial challenges, including genetic predisposition to progression of disease, specific immune responses (cytokine activity) to chlamydial infection, and identification of chlamydial antigen in tissues. Effectiveness of treatment is also being assessed in doxycycline- vs. azithromycin-treated animals, for lower and upper reproductive tract chlamydial infections. Studies specific to cytokine expression and immune responses to upper vs. lower tract disease are ongoing. Treatment assessments thus far have indicated that 3 of 7 doxycycline-treated animals failed treatment, compared with 1 of 4 azithromycin-treated animals. Of 7 animals receiving placebo treatment, 6 remained culture and/or LCR positive at the site of the cervix after completion of treatment. All animals were randomly assigned to treatment groups. The placebo treatment group is larger so that untreated animals ca n be followed for progression of disease studies. MHC testing has been performed on all 18 monkeys, though analysis of these results will take place after completion of all 45 animals to be enrolled in these studies. The analysis will be dependent on disease outcome for each animal. FUNDING NIH grants RR00166 and AI40307. Patton, D.L. and Lichtenwalner, A.B. Animal models for the study of chlamydial infections. In Chlamydial Infections, edited by R. Stephens et al., p. 641-650, 1998. Patton, D.L., Cumming, P.K., Cosgrove Sweeney, Y.T., and Kuo, C.C. In vivo uptake of Chlamydia trachomatis by fallopian tube epithelial cells is rapid. In Chlamydial Infections, edited by R. Stephens et al., p. 87-90, 1998.